[sdiy] circuit bending a yamaha fm piano question

[Andre Majorel]

On 2002-08-23 08:27 +0100, Peter Blackett wrote:

> just thought I would let you know that I've now looked at the info in
> the voice rom for the Yamaha pf15 piano .
> most of the eprom is blank ! 
> but the data for the 10 preset voices is there in blocks of 64 bytes .
> unfortunately the service manual doesn't tell you what each byte does .
> I can tell that there are two operator ic's so maybe each sound is a
> combination of two different sounds .But I don't know if the Fm
> generation is either 4 or 6 operator.
> putting in a Oberheim test rom [ happened to be the same eprom size ]
> gave mostly silence , but did give some organ like sounds .
> I got the idea to try other eproms from Marjan, who had done simialr
> things with an Oberheim drum machine.
> [the original sounds are only piano like instruments ].
> anyone know if there is an easy way to know which function each of the
> 64 data bytes does ?anyone want a copy of the voice eprom data ?
> regards Peter

A-ha, reverse engineering time ! Could you send me a copy of the
data ?

You could try filling the EPROM with 80h. It's more likely to
give you something audible than filling with extreme values.

-- 
André Majorel <amajorel at teaser.fr>
http://www.teaser.fr/~amajorel/